Updated by the Advanced Propulsion Centre in collaboration with and on behalf of the Automotive Council

Electric Machines Roadmap

Executive summary – Electric machines

• 2013 roadmap focused on a number of different motor architectures that could be applied for <40kW and >100kW electric machines.

• 2017 roadmap recognises that e-machine development is broadly focussed on both increasing technical performance and reducing cost in mass market products.

• 2017 roadmap has been built using a targets-based approach, informed by consensus amongst a wide range of industry and academic experts. Key targets are cost and power density.

• More emphasis has been placed on materials and manufacturing processes reflecting their importance in delivering cost competitive and sustainable solutions.

• A number of technology evolutions occur after 2025 which reflects the immaturity of the current e-machine automotive mass market and the need for targeted R&D on future applications.

• The roadmap reflects greater alignment with the power electronics roadmap, recognising that future product developments will lead to greater compatibility and integration.

Update process: The Electric Machine Roadmap was updated via a structured consensus-building process involving 46 experts

• A public workshop was held at the Advanced Propulsion Centre office in London, Stratford on the 25th January 2017

• The process was co-ordinated by the Advanced Propulsion Centre on behalf of Automotive Council

• The Advanced Propulsion Centre Electric Machine Spoke, supported by an expert Steering Group, helped to shape the roadmap before and after the workshop

Pre-event Common Assumptions Briefing

Breakout SessionsCollective Briefing

ProcessPost-Event Debrief

Pre-Event Email Post-Event Email1 day workshop with 40 attendees

Electric Machine Steering Committee and Workshop Attendees

Vehicle Manufacturer

Supplier

Technology Developer

Engineering Service Provider

Research

Other

46

Technical targets: Mass market adoption of ultra low emission vehicles underpins challenging cost and performance targets for electric machines

Drivers of change

• CO2 and air quality objectives challenge the universal application of ICE powertrains

• Electrification features in product plans of almost every OEM across all sectors

• Electric machines feature in all xEV formats and larger ancillary machines used for steering and cooling

• Despite electric machines being used for over 100 years, innovations are still needed in electric machines specifically designed for vehicle traction

• In order to meet mainstream automotive demands increased reliability, lower overall systems cost using widely available materials and higher performance are required

• In response to these challenges significant innovation is needed. Ambitious electric machine targets have been set which cannot be attained using existing designs.

Passenger Car TractionMotor¹

2017 2025 2035

Cost ($/kW)² 10 5.8 4.5

Continuous power density (kW/kg)

2.5 7 9

Continuous power density (kW/l)

7 25 30

Drive cycle efficiency (%)³ 86.5 92.5 93

Truck and Bus TractionMotor¹

2017 2025 2035

Cost ($/kW)² 60 15 12

Continuous power density (kW/kg)

1.5 2 2.5

Continuous power density (kW/l)

4.5 6 7

Drive cycle efficiency (%)³ 83 88 90

1) All assume 350V / 450Amps @ 65degC inlet2) Prices are 300% mark-up on material costs3) Drive cycle based on WLTP

Machine architectures and topologies

influences the performance and cost

of electric machines

Materials and manufacturing methods

are closely related, both are

fundamental to cost and performance

Several other technical aspects are

required to support improvement

How the electric machine is integrated with other

powertrain components is key to overall system efficiency

Technology categories: Parallel technical developments are required in electric machine architecture, integration, materials and supporting areas

Machine architectures can be designed for high

performance or for lower cost applications.

Existing high performance architectures can be

advanced by better thermal management (e.g.

internal rotor cooling, oil cooling, heat recovery,

targeted cooling of printed stators) and higher

speed capabilities (e.g. ceramic/air bearings,

more compact motors and faster inverter

switching frequencies). Lower cost machines

require reducing copper and iron losses (eddy &

hysteresis), cheaper motor housing solutions

and reducing costly material content with a

move to replace costly materials (such as

permanent magnets and copper windings) with

lower cost alternatives.

As connected and

autonomous vehicles

emerge, better fault

prediction and fault

tolerance mechanisms

are required.

Radical new machines designs will

be needed for both high

performance and low cost

machines. For lower cost machines,

advanced manufacturing methods

will drive down cost whereas higher

performance machines could be:

aggressively cooled, contain

advanced materials in the stator,

rotor and windings or be novel

designs leveraged from other

sectors

Advanced high performance

machine architecture concepts,

that have not traditionally been

used for automotive, could be

introduced to improve

performance for specialist

applications. These advanced

architectures can be defined by

how they are integrated into the

vehicle (e.g. distributed

machines such as wheel-hub

motors) or their novel

magnetic/mechanical design

(i.e. axial, radial and transverse

flux motors).

Machine architecture: Current machine architecture can be improved but new designs will be needed to meet longer term targets

As mild hybrids become more prominent to meet

near term emissions legislation, machines will

require closer coupling with the transmission and

engines to deliver the optimum performance

For the next generation mild hybrids, e-machines will be co-

developed with the thermal propulsion system and transmissions to

enable downsizing, potentially requiring a larger machine.

A fully-integrated manufacturing route

to integrated drives - where the power

electronics and machine are

fabricated together - has the potential

for dramatic cost reductions

Integrated drives are a potential option for OEMs, however

challenges include: manufacturability; integrated cooling

systems; graceful failsafe mechanisms; drives for multi-phase

& distributed machines; achieving higher switching

frequencies to support high frequency (smaller) electrical

machines and adoption of switched reluctance drives.

Machine integration: Integrating an electric machine effectively into the vehicle powertrain is essential to overall system efficiency

Winding strategies (e.g. distributed, concentrated) are key to maximising

the performance and reducing machine losses. Key challenges include:

increasing material fill factor; improving insulation and isolation methods

(e.g thin enamels, nano-materials, self-repairing insulation, better materials

for coil encapsulation) improved winding processes (e.g. litz wire) and fully

automating the manufacturing process to enable lower cost machines.

Introducing advanced additive layer manufacturing can

remove the requirement for winding processes if complex

machine geometries can be manufactured at high volumes

Winding materials offer the potential for dramatically lower costs or radically improved performance. Aluminium windings are

cheaper, lighter and more readily recyclable with steel than copper thus making it a potential replacement. Alternative higher

performance materials (e.g. carbon nanotubes embedded in copper or on the surface, graphene; nano-materials; high

temperature superconductors) offer higher conductivity and lower losses but currently command a price premium.

Materials and manufacturing: New processes and materials for windings can significantly improve performance or lower cost

Advances in electrical steels magnetic and chemical properties can reduce eddy and hysteresis losses,

improving overall machine efficiency. Short term challenges include: automotive relevant measurement

methods and material models/characterisation, improved bonding and coating technologies (i.e. self bonding

coatings), achieving lower loss thinner grade steels, higher alloy content grades for automotive volume.

Longer term challenges include utilising more grain orientated steels, cost effectively introducing other metals

(e.g. cobalt, manganese, vanadium, chromium) and developing tailored steels with localised optimisation

Soft magnetic composites are less commonly used in automotive applications compared to

electrical steels, but allow more complex, 3-D shapes to be manufactured through net shape

manufacturing. Challenges include improvements in losses and permeability, achieving

smaller grain sizes and achieving significant cost reduction in the manufacturing processes.

Materials and manufacturing: Improvements in the material properties of electrical steels and soft magnetic composites can deliver cost and performance improvements

Heavy rare earth materials such as

Dysprosium are added to improve the

temperature resistance of Neodymium but are

expensive and strongly concentrated in

China. There is a desire that these should be

eliminated to reduce costs and supply risks.

New manufacturing processes are required to: allow thinner

laminations to reduce eddy current losses; produce PMs with improved

strength, durability and high temperature capability; manufacture new

materials with improved electrical resistivity

Light rare earth magnets (e.g. Neodymium) are a significant cost to current electric

machines. Architectures that do not use magnets (i.e. induction and switched reluctance)

or alternative magnetic materials (i.e. ferrite magnets) are potential solutions.

Utilising recycled permanent magnets that maintain performance

characteristics will enable a closed-loop supply chain for rare earths improving

the cost and environmental performance of permanent magnet machines.

Materials and manufacturing: Permanent magnet electric machines can be high cost so effective use of rare earth materials is needed

Refined manufacturing techniques could improve performance, enable

higher volumes of existing machine topologies and the manufacture of new

topologies. Increased automation (utilising tooling expertise from other

sectors) could improve consistency and enable lower cost machines.Machine will be designed and

manufactured with disassembly

and end-of-life in mind. New

recycling processes to enable

sensing, sorting, separation,

purification and reprocessing of

materials will also improve the life

cycle environmental sustainability

of electric machines.

Advanced data analytics,

V2V and self-learning

software could enable

electric machines to self-

adapt for high efficiency,

peak power or reliability

based on driving styles

Advanced controls will help manage NVH, efficiency optimisation

with the potential for wireless and/or sensor less control

Enablers: A number of supporting innovations are essential to meet the performance and cost targets

Glossary: Explanation of acronyms and terms not described in the roadmap due to space constraints

• CAVs (Connected and autonomous vehicles) – Connected and autonomous vehicles is an umbrella term to capture the

varying levels of autonomy and technologies relating to self-driving vehicles.

• Dy (Dysprosium) – Dysprosium is a heavy rare earth material that is used alongside Neodymium. Dy has been essential in

making it possible to use NdFeB magnets in high power density applications such as vehicle traction

• HTS (High temperature superconductors) – Developmental conductor materials that are extremely conductive compared to

copper but require low temperatures (between -240⁰C and -70⁰C) in order to conduct efficiently.

• LCA (Life cycle analysis) – Identifying the total environmental impact of a given product.

• Nd (Neodymium) – Neodymium is a light rare earth material that is widely used as a rare earth material in automotive electric

machines. In order to make a usable magnet, Neodymium is usually alloyed with Iron and Boron to create NdFeB magnets.

• SMCs (Soft magnetic composites) – Soft magnetic composites (SMC’s) are an alternative to electrical steels. They are made

of iron powder particles coated with an electrically insulating layer and they can be moulded into complex shape under high

pressure in a die.

• TPS (Thermal propulsion systems) – Thermal propulsion system is the Automotive Council’s new term for internal combustion

engines. It is a device that integrates an engine or fuel cell with thermal and / or electrical systems to manage power delivery to

the wheels and recover waste energy to improved performance and efficiency. The key feature of a TPS is that the primary

energy is stored chemically (rather than electrochemically like in a battery)

• V2X (Vehicle-to-X) – Vehicle-to-X refers to an intelligent transport system where all vehicles and infrastructure systems are

interconnected with each other.